K2 - KPA100 RS232 interface repair

K2 - KPA100 RS232 interface repair

I had been using an Elecraft USB/serial cable with my recently acquired K2 and the PC communications worked properly. In debugging a software problem, it was suggested that I try using a real serial port, which I did. Unfortunately, I was unaware that I wasn't supposed to use a standard RS232 cable. So now, the K2's port won't work with the USB/serial cable either and I assume that the interface in the KPA-100 was damaged. I guess that U4 (MAX 1406) is a prime suspect for failure in this case. Any suggestions?

Re: K2 - KPA100 RS232 interface repair

Anyone who has purchased a used K2 needs to take notice, lest it happen
to you too.

That connector is marked AUX I/O for exactly that reason, it is not a
computer RS-232 connector even though it contains TXD, RXD and signal
ground. As a result, one must always use the special cable that is
built as part of the KPA100 to connect to a computer serial port.

You are not likely to have damaged anything in the KPA100 when
connecting a standard serial cable to the K2, although KPA100 U6 may
have a damaged output at pin 6, and the inductors located just behind
the DE-9 connector should be checked for continuity.
The TXD and RXD signals in the serial cable will connect to U4 just the
same as if the special cable were used.

You could have also damaged the computer serial port because pin 1 was
grounded by the K2.

You will find most of the damage will be in the base K2.
Internal signals AUXBUS and VRFDET could have caused the MCU IC to be
damaged as well as the KSB2.
The fact that the 8R voltage rail appears on that connector, that may
have caused further damage.

Re: K2 - KPA100 RS232 interface repair

Hi Don. I'm sure you're aware that the RS232 spec includes the
description of voltage levels, and if you're going to refer to an
interface as RS232 (as Elecraft does in many places) then you're
implying that the normal RS232 signal levels will be used. A user
shouldn't be required to read a one hundred page manual before plugging
in a connector when every other such connector works in the conventional
way. Having been a designer using RS232 interfaces 45 years ago, I
would have been executed had I designed something like this.

Anyway, maybe you can help me determine what areas to focus on in the
repair. Here's what I know:

1. The RF chokes RFC6-9 are all intact.
2. The ALC is functioning properly - the power control properly controls
the output
3. U1 in the KPS-100 appears to be functioning as the relays are being
activated at the right time as I switch through the bands.
4. Data sent from Hyperterminal through the USB/serial converter to the
K2 shows up on Pin 6 of the KPA-100 U4 (the Max1706) and can be seen at
pin 26 of the K2 MCU (U6). But, the K2 doesn't act on the commands that
are sent.
5. The voltage on pin 5 of U4 (MAX1406) is -15.4 VDC, seems that
indicates U4 is toast?

I haven't observed any other problems. I found the document written by
Gary Surrency and Tom Hammond regarding this situation. Which leads me
to some questions:

1. Reference is made to possible damage to the KSB2. Do you know what
the symptom would be in that case?
2. Apparently, any damage to the MCU IC might be isolated to just the
input from the interface - pin 26. I say that because everything else
appears to function normally. Are you aware of anything else I might
check for regarding the MCU function?

73, Floyd

On 8/22/2015 3:16 PM, Don Wilhelm wrote:

> Anyone who has purchased a used K2 needs to take notice, lest it
> happen to you too.
>
> That connector is marked AUX I/O for exactly that reason, it is not a
> computer RS-232 connector even though it contains TXD, RXD and signal
> ground. As a result, one must always use the special cable that is
> built as part of the KPA100 to connect to a computer serial port.
>
> You are not likely to have damaged anything in the KPA100 when
> connecting a standard serial cable to the K2, although KPA100 U6 may
> have a damaged output at pin 6, and the inductors located just behind
> the DE-9 connector should be checked for continuity.
> The TXD and RXD signals in the serial cable will connect to U4 just
> the same as if the special cable were used.
>
> You could have also damaged the computer serial port because pin 1 was
> grounded by the K2.
>
> You will find most of the damage will be in the base K2.
> Internal signals AUXBUS and VRFDET could have caused the MCU IC to be
> damaged as well as the KSB2.
> The fact that the 8R voltage rail appears on that connector, that may
> have caused further damage.
>
> 73,
> Don W3FPR
>

Re: K2 - KPA100 RS232 interface repair

Floyd,

You say the voltage at U4 pin 5 is -15.4 volts, and that *may* be a
perfectly valid voltage - that is a MARK.
It should not be constantly that way, so check U4 pin 12 - if it is
zero, then the MAX1406 is behaving properly in response. That line
originates from the MCU (Control Board U6) pin 25, and should be +5v
under normal conditions, but pulses to zero when the K2 sends data.

If you find KPA100 U4 pin 12 at 5 volts while pin 5 is going negative,
then replace U4.
OTOH, if U4 pin 12 is at zero volts, suspect the K2 MCU or some problem
on the signal line between those points.
As a quick check on whether the base K2 or KPA100 is pulling that signal
to zero, remove the KPA100 ribbon cable, then power the base K2 and see
whether CB U6 pin 25 goes to +5v with the ribbon cable removed. If it
stays at 0 volts, remove the MCU and make a resistance measurement on U6
pin 25 to make sure it is not shorted - if you read a high resistance,
replace the MCU IC.

The most likely symptom if the KSB2 board has been damaged from plugging
in a serial cable is that you could have damaged either the KSB2 MCU
(AUXBUS line), or Q1 (high voltage on the VRFDET line or the ALC line
can do damage).

Note that if you were previously connecting the USB to serial adapter
directly to the KPA100 AUX I/O connector, it may be possible that no
damage would occur *if* the voltage out of the adapter did not exceed 5
volts and never went negative. In the PC world of short RS-232
signalling, some try to "get away' with those levels, where a real
serial card will typically have voltages in excess of +/-12 volts.
So if you did not previously use the special cable, you will need to
build one - the instructions are in the KPA100 manual page 60.

73,
Don W3FPR

On 8/22/2015 4:28 PM, Floyd Sense wrote:

>
> Anyway, maybe you can help me determine what areas to focus on in the
> repair. Here's what I know:
>
> 1. The RF chokes RFC6-9 are all intact.
> 2. The ALC is functioning properly - the power control properly
> controls the output
> 3. U1 in the KPS-100 appears to be functioning as the relays are being
> activated at the right time as I switch through the bands.
> 4. Data sent from Hyperterminal through the USB/serial converter to
> the K2 shows up on Pin 6 of the KPA-100 U4 (the Max1706) and can be
> seen at pin 26 of the K2 MCU (U6). But, the K2 doesn't act on the
> commands that are sent.
> 5. The voltage on pin 5 of U4 (MAX1406) is -15.4 VDC, seems that
> indicates U4 is toast?
>
> I haven't observed any other problems. I found the document written
> by Gary Surrency and Tom Hammond regarding this situation. Which
> leads me to some questions:
>
> 1. Reference is made to possible damage to the KSB2. Do you know
> what the symptom would be in that case?
> 2. Apparently, any damage to the MCU IC might be isolated to just the
> input from the interface - pin 26. I say that because everything else
> appears to function normally. Are you aware of anything else I might
> check for regarding the MCU function?
>
> 73, Floyd
>
>
> On 8/22/2015 3:16 PM, Don Wilhelm wrote:
>> Anyone who has purchased a used K2 needs to take notice, lest it
>> happen to you too.
>>
>> That connector is marked AUX I/O for exactly that reason, it is not a
>> computer RS-232 connector even though it contains TXD, RXD and signal
>> ground. As a result, one must always use the special cable that is
>> built as part of the KPA100 to connect to a computer serial port.
>>
>> You are not likely to have damaged anything in the KPA100 when
>> connecting a standard serial cable to the K2, although KPA100 U6 may
>> have a damaged output at pin 6, and the inductors located just behind
>> the DE-9 connector should be checked for continuity.
>> The TXD and RXD signals in the serial cable will connect to U4 just
>> the same as if the special cable were used.
>>
>> You could have also damaged the computer serial port because pin 1
>> was grounded by the K2.
>>
>> You will find most of the damage will be in the base K2.
>> Internal signals AUXBUS and VRFDET could have caused the MCU IC to be
>> damaged as well as the KSB2.
>> The fact that the 8R voltage rail appears on that connector, that may
>> have caused further damage.
>>
>> 73,
>> Don W3FPR
>>
>
>

Re: K2 - KPA100 RS232 interface repair

OK - many thanks, Don. I'll get busy
looking at those things.

73, Floyd

On 8/22/2015 6:33 PM, Don Wilhelm-4 [via Elecraft] wrote:

Floyd,

You say the voltage at U4 pin 5 is -15.4 volts, and that *may* be
a
perfectly valid voltage - that is a MARK.
It should not be constantly that way, so check U4 pin 12 - if it
is
zero, then the MAX1406 is behaving properly in response. That
line
originates from the MCU (Control Board U6) pin 25, and should be
+5v
under normal conditions, but pulses to zero when the K2 sends
data.

If you find KPA100 U4 pin 12 at 5 volts while pin 5 is going
negative,
then replace U4.
OTOH, if U4 pin 12 is at zero volts, suspect the K2 MCU or some
problem
on the signal line between those points.
As a quick check on whether the base K2 or KPA100 is pulling that
signal
to zero, remove the KPA100 ribbon cable, then power the base K2
and see
whether CB U6 pin 25 goes to +5v with the ribbon cable removed.
If it
stays at 0 volts, remove the MCU and make a resistance measurement
on U6
pin 25 to make sure it is not shorted - if you read a high
resistance,
replace the MCU IC.

The most likely symptom if the KSB2 board has been damaged from
plugging
in a serial cable is that you could have damaged either the KSB2
MCU
(AUXBUS line), or Q1 (high voltage on the VRFDET line or the ALC
line
can do damage).

Note that if you were previously connecting the USB to serial
adapter
directly to the KPA100 AUX I/O connector, it may be possible that
no
damage would occur *if* the voltage out of the adapter did not
exceed 5
volts and never went negative. In the PC world of short RS-232
signalling, some try to "get away' with those levels, where a real
serial card will typically have voltages in excess of +/-12 volts.
So if you did not previously use the special cable, you will need
to
build one - the instructions are in the KPA100 manual page 60.

73,
Don W3FPR

On 8/22/2015 4:28 PM, Floyd Sense wrote:

>
> Anyway, maybe you can help me determine what areas to focus
on in the
> repair. Here's what I know:
>
> 1. The RF chokes RFC6-9 are all intact.
> 2. The ALC is functioning properly - the power control
properly
> controls the output
> 3. U1 in the KPS-100 appears to be functioning as the
relays are being
> activated at the right time as I switch through the bands.
> 4. Data sent from Hyperterminal through the USB/serial
converter to
> the K2 shows up on Pin 6 of the KPA-100 U4 (the Max1706)
and can be
> seen at pin 26 of the K2 MCU (U6). But, the K2 doesn't act
on the
> commands that are sent.
> 5. The voltage on pin 5 of U4 (MAX1406) is -15.4 VDC, seems
that
> indicates U4 is toast?
>
> I haven't observed any other problems. I found the
document written
> by Gary Surrency and Tom Hammond regarding this situation.
Which
> leads me to some questions:
>
> 1. Reference is made to possible damage to the KSB2. Do
you know
> what the symptom would be in that case?
> 2. Apparently, any damage to the MCU IC might be isolated
to just the
> input from the interface - pin 26. I say that because
everything else
> appears to function normally. Are you aware of anything
else I might
> check for regarding the MCU function?
>
> 73, Floyd
>
>
> On 8/22/2015 3:16 PM, Don Wilhelm wrote:
>> Anyone who has purchased a used K2 needs to take
notice, lest it
>> happen to you too.
>>
>> That connector is marked AUX I/O for exactly that
reason, it is not a
>> computer RS-232 connector even though it contains TXD,
RXD and signal
>> ground. As a result, one must always use the special
cable that is
>> built as part of the KPA100 to connect to a computer
serial port.
>>
>> You are not likely to have damaged anything in the
KPA100 when
>> connecting a standard serial cable to the K2, although
KPA100 U6 may
>> have a damaged output at pin 6, and the inductors
located just behind
>> the DE-9 connector should be checked for continuity.
>> The TXD and RXD signals in the serial cable will
connect to U4 just
>> the same as if the special cable were used.
>>
>> You could have also damaged the computer serial port
because pin 1
>> was grounded by the K2.
>>
>> You will find most of the damage will be in the base
K2.
>> Internal signals AUXBUS and VRFDET could have caused
the MCU IC to be
>> damaged as well as the KSB2.
>> The fact that the 8R voltage rail appears on that
connector, that may
>> have caused further damage.
>>
>> 73,
>> Don W3FPR
>>
>
>

Re: K2 - KPA100 RS232 interface repair

I've owned and operated a pair of K2s, both of which I bought used.
Elecraft makes it very clear that the DB9 connector on the K2 is NOT an
RS232 interface, that it is not RS232 compliant, and that a standard
RS232 cable should NOT be used. Rather, the DB9 connector provides both
serial control AND several control functions.

The DB9 connector is a generic part, and can be used for many things
besides RS232. It is also well known that while the RS232 Standard
defines voltage levels, MANY modern products produce far less than those
levels.

I've owned a lot of gear in my lifetime, and the first thing I do is
open the manual, study it, study the wiring of the various connectors,
study the specs, and study the operating instructions.

73, Jim K9YC

On Sat,8/22/2015 1:28 PM, Floyd Sense wrote:
> Hi Don. I'm sure you're aware that the RS232 spec includes the
> description of voltage levels, and if you're going to refer to an
> interface as RS232 (as Elecraft does in many places) then you're
> implying that the normal RS232 signal levels will be used. A user
> shouldn't be required to read a one hundred page manual before
> plugging in a connector when every other such connector works in the
> conventional way. Having been a designer using RS232 interfaces 45
> years ago, I would have been executed had I designed something like this.

I've owned and operated a pair of K2s, both of which I bought used.
Elecraft makes it very clear that the DB9 connector on the K2 is NOT an
RS232 interface, that it is not RS232 compliant, and that a standard
RS232 cable should NOT be used. Rather, the DB9 connector provides both
serial control AND several control functions.

The DB9 connector is a generic part, and can be used for many things besides
RS232. It is also well known that while the RS232 Standard defines voltage
levels, MANY modern products produce far less than those levels.

I've owned a lot of gear in my lifetime, and the first thing I do is open
the manual, study it, study the wiring of the various connectors, study the
specs, and study the operating instructions.

73, Jim K9YC

On Sat,8/22/2015 1:28 PM, Floyd Sense wrote:
> Hi Don. I'm sure you're aware that the RS232 spec includes the
> description of voltage levels, and if you're going to refer to an
> interface as RS232 (as Elecraft does in many places) then you're
> implying that the normal RS232 signal levels will be used. A user
> shouldn't be required to read a one hundred page manual before
> plugging in a connector when every other such connector works in the
> conventional way. Having been a designer using RS232 interfaces 45
> years ago, I would have been executed had I designed something like this.

Re: K2 - KPA100 RS232 interface repair

Hi Jim. Well, when this incident occurred, I was deep into working on
an associated software problem and needed to quickly try the PC serial
port directly. I agree with you comment about reading the manual and in
fact I did so just a couple of weeks back when I acquired this unit.
Unfortunately, at my age, I don't always recall 100% of what I read.
Now that I have this problem, of course I remember reading all about
needing the special cable

But, I disagree regarding the use of the DB9 connector on the K2. Having
worked on tons of gear with communications ports, I've never run into
one that purportedly used an RS232 interface, but would self-destruct if
a real RS232 interface were attached. The KPA-100 manual clearly
describes it as an RS232 interface and the schematic has it labeled as
such. If it doesn't support RS232 voltage levels, then it isn't an
RS232 interface in my book. And I know that there are devices that use
a DB9 connector but are not RS232 compliant, but that isn't the issue here.

In the document that Gary Surrency and Tom Hammond wrote on the subject
several years ago, they clearly pointed out the need for a more
prominent label warning of the possible consequences of connecting the
wrong cable. Had I seen such a warning, I'd have remembered the reason
for it and would have avoided the problem. At any rate, the worst result
should be a failure to communicate and not the destruction of several
important components in the unit. Having read many of your writings, I
doubt that you'd have ever designed something with that sort of risk
involved.

When I get everything working again, I plan to document in detail what
fails, how to determine if it had failed and what to do about it.
Current documentation on that is rather lacking and I'll bet that there
are scores of K2s out there with the same problem.

73, Floyd - K8AC

On 8/22/2015 7:26 PM, Jim Brown-10 [via Elecraft] wrote:

> Hi Floyd,
>
> I've owned and operated a pair of K2s, both of which I bought used.
> Elecraft makes it very clear that the DB9 connector on the K2 is NOT an
> RS232 interface, that it is not RS232 compliant, and that a standard
> RS232 cable should NOT be used. Rather, the DB9 connector provides both
> serial control AND several control functions.
>
> The DB9 connector is a generic part, and can be used for many things
> besides RS232. It is also well known that while the RS232 Standard
> defines voltage levels, MANY modern products produce far less than those
> levels.
>
> I've owned a lot of gear in my lifetime, and the first thing I do is
> open the manual, study it, study the wiring of the various connectors,
> study the specs, and study the operating instructions.
>
> 73, Jim K9YC
>
>

Re: K2 - KPA100 RS232 interface repair

The K3S has a RJ-45 connector for the RS-232 communications. Now that's
different! Of course they supply a cable with a RJ-45 on one end and a
DB-9F on the other. And then to keep everybody happy, there is what
appears to be a 15 pin VGA connector that is the ACC connector to
provide band data and such. The manual clearly states "This is not a
VGA video connector".

Yes it is very important to read and understand the manual before
plugging or inserting any connector into any hole on any radio today.
It seems most hams think if it plugs in, then it should work.

73
Bob, K4TAX
K3S s/n 10,163

On 8/22/2015 7:17 PM, Richard W. Solomon wrote:

> It seems to me that using a DB-9 connector for non-RS232 uses is taking the
> Easy way out.
> There are numerous other connectors that could be used to alleviate any
> Misunderstanding.
>
> Not everyone goes through manuals with a fine tooth comb to locate the
> "gotchas".
>
> 73, Dick, W1KSZ
>
> -----Original Message-----
> From: Elecraft [mailto:[hidden email]] On Behalf Of Jim
> Brown
> Sent: Saturday, August 22, 2015 4:25 PM
> To: [hidden email]> Subject: Re: [Elecraft] K2 - KPA100 RS232 interface repair
>
> Hi Floyd,
>
> I've owned and operated a pair of K2s, both of which I bought used.
> Elecraft makes it very clear that the DB9 connector on the K2 is NOT an
> RS232 interface, that it is not RS232 compliant, and that a standard
> RS232 cable should NOT be used. Rather, the DB9 connector provides both
> serial control AND several control functions.
>
> The DB9 connector is a generic part, and can be used for many things besides
> RS232. It is also well known that while the RS232 Standard defines voltage
> levels, MANY modern products produce far less than those levels.
>
> I've owned a lot of gear in my lifetime, and the first thing I do is open
> the manual, study it, study the wiring of the various connectors, study the
> specs, and study the operating instructions.
>
> 73, Jim K9YC
>
>
>
> On Sat,8/22/2015 1:28 PM, Floyd Sense wrote:
>> Hi Don. I'm sure you're aware that the RS232 spec includes the
>> description of voltage levels, and if you're going to refer to an
>> interface as RS232 (as Elecraft does in many places) then you're
>> implying that the normal RS232 signal levels will be used. A user
>> shouldn't be required to read a one hundred page manual before
>> plugging in a connector when every other such connector works in the
>> conventional way. Having been a designer using RS232 interfaces 45
>> years ago, I would have been executed had I designed something like this.
> ______________________________________________________________
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>

Re: K2 - KPA100 RS232 interface repair

Most of us built our K2/KPA100/KAT100 way back;
that was the only way you could buy them, not
factory-built nor factory-assembled. That did
require that we apply the "fine tooth comb"
approach to the manual, since we soldered every
connection to every part. As a result I'm still,
12 years or so after building my KPA100, aware of
the issue.

73, Phil W7OX

On 8/22/15 5:17 PM, Richard W. Solomon wrote:

> It seems to me that using a DB-9 connector for non-RS232 uses is taking the
> Easy way out.
> There are numerous other connectors that could be used to alleviate any
> Misunderstanding.
>
> Not everyone goes through manuals with a fine tooth comb to locate the
> "gotchas".
>
> 73, Dick, W1KSZ
>
> -----Original Message-----
> From: Elecraft [mailto:[hidden email]] On Behalf Of Jim
> Brown
> Sent: Saturday, August 22, 2015 4:25 PM
> To: [hidden email]> Subject: Re: [Elecraft] K2 - KPA100 RS232 interface repair
>
> Hi Floyd,
>
> I've owned and operated a pair of K2s, both of which I bought used.
> Elecraft makes it very clear that the DB9 connector on the K2 is NOT an
> RS232 interface, that it is not RS232 compliant, and that a standard
> RS232 cable should NOT be used. Rather, the DB9 connector provides both
> serial control AND several control functions.
>
> The DB9 connector is a generic part, and can be used for many things besides
> RS232. It is also well known that while the RS232 Standard defines voltage
> levels, MANY modern products produce far less than those levels.
>
> I've owned a lot of gear in my lifetime, and the first thing I do is open
> the manual, study it, study the wiring of the various connectors, study the
> specs, and study the operating instructions.
>
> 73, Jim K9YC
>
>
>
> On Sat,8/22/2015 1:28 PM, Floyd Sense wrote:
>> Hi Don. I'm sure you're aware that the RS232 spec includes the
>> description of voltage levels, and if you're going to refer to an
>> interface as RS232 (as Elecraft does in many places) then you're
>> implying that the normal RS232 signal levels will be used. A user
>> shouldn't be required to read a one hundred page manual before
>> plugging in a connector when every other such connector works in the
>> conventional way. Having been a designer using RS232 interfaces 45
>> years ago, I would have been executed had I designed something like this.

Re: K2 - KPA100 RS232 interface repair

The RJ-45 connector is now defined in the RS-232 standard, as is the
DE-9 and DB-25.
Of course, Ethernet also uses the RJ-45 connector, as do multi-line
telephone sets. Those are *not* interchangeable functions. You would
not want to plug an RJ-45 RS-232 cable into your RJ-45 ethernet router
jack or into your multi-line telephone system.
Make no assumptions about connectors, for they are a "just a connector".

Another example:
The older PCs used the DB-25 for a printer port. How do you tell the
difference between a printer port and a 25 pin serial port connector? -
you refer to the manual for the device in question and look for a
clearly defined label.
At our church, there is a sound console that has a DB-25 connector -
should I assume that is a printer port, or a serial port just because
those are connectors commonly used for those applications - of course
not - the connector on the sound console is for expansion devices.

So, know what you are plugging into before connecting cables (even if
they fit) - if it is labeled as RS-232, then plug away, but if it is
labeled with anything different, check the manual before plugging. That
fact goes for any device with a connector, it is not just for the K2.

As another parallel, RCA jacks are used for many purposes - antenna
connections, audio connections, and yes even power connections. Would
you plug anything into an RCA jack assuming it was an audio connector
without carefully heeding the label or referring to the equipment manual?

A connector is "just a connector". Just because it looks like the
connector in one piece of gear that you happen to be familiar with does
not mean it serves the same purpose on everything else. Take DIN
connectors as an example - they are common on many pieces of ham gear.
Why would one assume that a 6 pin DIN connector on a Yaesu transceiver
has the same pinout as that on an Icom. I hope I have made my point and
will belabor it no more.

73,
Don W3FPR

On 8/22/2015 8:31 PM, Bob McGraw - K4TAX wrote:

> The K3S has a RJ-45 connector for the RS-232 communications. Now
> that's different! Of course they supply a cable with a RJ-45 on one
> end and a DB-9F on the other. And then to keep everybody happy, there
> is what appears to be a 15 pin VGA connector that is the ACC connector
> to provide band data and such. The manual clearly states "This is not
> a VGA video connector".
>
> Yes it is very important to read and understand the manual before
> plugging or inserting any connector into any hole on any radio today.
> It seems most hams think if it plugs in, then it should work.
>

Re: K2 - KPA100 RS232 interface repair

On Sat,8/22/2015 5:17 PM, Richard W. Solomon wrote:
> It seems to me that using a DB-9 connector for non-RS232 uses is taking the Easy way out. There are numerous other connectors that could be used to alleviate any Misunderstanding.

I see it quite differently. The K2 was a kit, designed to be built by
mere mortals, not machines. The DB-series connectors are widely
available from good industrial sources and are easy to work on. There's
also the matter of panel real estate. Yes, there are other connectors,
but I can't think of a decent alternative that fits the above objectives.

On Sat,8/22/2015 5:17 PM, Richard W. Solomon wrote:
> It seems to me that using a DB-9 connector for non-RS232 uses is taking
the Easy way out. There are numerous other connectors that could be used to
alleviate any Misunderstanding.

I see it quite differently. The K2 was a kit, designed to be built by mere
mortals, not machines. The DB-series connectors are widely available from
good industrial sources and are easy to work on. There's also the matter of
panel real estate. Yes, there are other connectors, but I can't think of a
decent alternative that fits the above objectives.

Re: K2 - KPA100 RS232 interface repair

RJ45 is commonly used for RS232C. Millions of Cisco routers and switches built over the past 20+ years use this arrangement, as do many other devices. I have a half dozen of these cables - they once were shipped with the router. Although I don't know for sure, I'll bet the pinout is the same as Cisco.

I can make up 10 RJ45 connectors in the time it takes to make a soldered DB9.

Historically, RS232 was used in electromagnetic applications where there was a need to drive a relay with line levels. Since modern equipment doesn't need this - since TTL became commonplace in the 1970's - and since many lower power devices no longer have 12V power supplies, it has been practice to observe a ONE state at a voltage of 3V+.

> On Aug 22, 2015, at 8:31 PM, Bob McGraw - K4TAX <[hidden email]> wrote:
>
> The K3S has a RJ-45 connector for the RS-232 communications. Now that's different! Of course they supply a cable with a RJ-45 on one end and a DB-9F on the other. And then to keep everybody happy, there is what appears to be a 15 pin VGA connector that is the ACC connector to provide band data and such. The manual clearly states "This is not a VGA video connector".
>
> Yes it is very important to read and understand the manual before plugging or inserting any connector into any hole on any radio today. It seems most hams think if it plugs in, then it should work.
>
> 73
> Bob, K4TAX
> K3S s/n 10,163
>
>> On 8/22/2015 7:17 PM, Richard W. Solomon wrote:
>> It seems to me that using a DB-9 connector for non-RS232 uses is taking the
>> Easy way out.
>> There are numerous other connectors that could be used to alleviate any
>> Misunderstanding.
>>
>> Not everyone goes through manuals with a fine tooth comb to locate the
>> "gotchas".
>>
>> 73, Dick, W1KSZ
>>
>> -----Original Message-----
>> From: Elecraft [mailto:[hidden email]] On Behalf Of Jim
>> Brown
>> Sent: Saturday, August 22, 2015 4:25 PM
>> To: [hidden email]>> Subject: Re: [Elecraft] K2 - KPA100 RS232 interface repair
>>
>> Hi Floyd,
>>
>> I've owned and operated a pair of K2s, both of which I bought used.
>> Elecraft makes it very clear that the DB9 connector on the K2 is NOT an
>> RS232 interface, that it is not RS232 compliant, and that a standard
>> RS232 cable should NOT be used. Rather, the DB9 connector provides both
>> serial control AND several control functions.
>>
>> The DB9 connector is a generic part, and can be used for many things besides
>> RS232. It is also well known that while the RS232 Standard defines voltage
>> levels, MANY modern products produce far less than those levels.
>>
>> I've owned a lot of gear in my lifetime, and the first thing I do is open
>> the manual, study it, study the wiring of the various connectors, study the
>> specs, and study the operating instructions.
>>
>> 73, Jim K9YC
>>
>>
>>
>>> On Sat,8/22/2015 1:28 PM, Floyd Sense wrote:
>>> Hi Don. I'm sure you're aware that the RS232 spec includes the
>>> description of voltage levels, and if you're going to refer to an
>>> interface as RS232 (as Elecraft does in many places) then you're
>>> implying that the normal RS232 signal levels will be used. A user
>>> shouldn't be required to read a one hundred page manual before
>>> plugging in a connector when every other such connector works in the
>>> conventional way. Having been a designer using RS232 interfaces 45
>>> years ago, I would have been executed had I designed something like this.
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft>> Help: http://mailman.qth.net/mmfaq.htm>> Post: mailto:[hidden email]>>
>> This list hosted by: http://www.qsl.net>> Please help support this email list: http://www.qsl.net/donate.html Message
>> delivered to [hidden email]>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft>> Help: http://mailman.qth.net/mmfaq.htm>> Post: mailto:[hidden email]>>
>> This list hosted by: http://www.qsl.net>> Please help support this email list: http://www.qsl.net/donate.html>> Message delivered to [hidden email]>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft> Help: http://mailman.qth.net/mmfaq.htm> Post: mailto:[hidden email]>
> This list hosted by: http://www.qsl.net> Please help support this email list: http://www.qsl.net/donate.html> Message delivered to [hidden email]

RJ45 is commonly used for RS232C. Millions of Cisco routers and switches
built over the past 20+ years use this arrangement, as do many other
devices. I have a half dozen of these cables - they once were shipped with
the router. Although I don't know for sure, I'll bet the pinout is the same
as Cisco.

I can make up 10 RJ45 connectors in the time it takes to make a soldered
DB9.

Historically, RS232 was used in electromagnetic applications where there was
a need to drive a relay with line levels. Since modern equipment doesn't
need this - since TTL became commonplace in the 1970's - and since many
lower power devices no longer have 12V power supplies, it has been practice
to observe a ONE state at a voltage of 3V+.

> On Aug 22, 2015, at 8:31 PM, Bob McGraw - K4TAX <[hidden email]>
wrote:
>
> The K3S has a RJ-45 connector for the RS-232 communications. Now that's
different! Of course they supply a cable with a RJ-45 on one end and a
DB-9F on the other. And then to keep everybody happy, there is what appears
to be a 15 pin VGA connector that is the ACC connector to provide band data
and such. The manual clearly states "This is not a VGA video connector".
>
> Yes it is very important to read and understand the manual before plugging
or inserting any connector into any hole on any radio today. It seems most
hams think if it plugs in, then it should work.

>
> 73
> Bob, K4TAX
> K3S s/n 10,163
>
>> On 8/22/2015 7:17 PM, Richard W. Solomon wrote:
>> It seems to me that using a DB-9 connector for non-RS232 uses is
>> taking the Easy way out.
>> There are numerous other connectors that could be used to alleviate
>> any Misunderstanding.
>>
>> Not everyone goes through manuals with a fine tooth comb to locate
>> the "gotchas".
>>
>> 73, Dick, W1KSZ
>>
>> -----Original Message-----
>> From: Elecraft [mailto:[hidden email]] On Behalf Of
>> Jim Brown
>> Sent: Saturday, August 22, 2015 4:25 PM
>> To: [hidden email]>> Subject: Re: [Elecraft] K2 - KPA100 RS232 interface repair
>>
>> Hi Floyd,
>>
>> I've owned and operated a pair of K2s, both of which I bought used.
>> Elecraft makes it very clear that the DB9 connector on the K2 is NOT
>> an
>> RS232 interface, that it is not RS232 compliant, and that a standard
>> RS232 cable should NOT be used. Rather, the DB9 connector provides
>> both serial control AND several control functions.
>>
>> The DB9 connector is a generic part, and can be used for many things
>> besides RS232. It is also well known that while the RS232 Standard
>> defines voltage levels, MANY modern products produce far less than those

levels.

>>
>> I've owned a lot of gear in my lifetime, and the first thing I do is
>> open the manual, study it, study the wiring of the various
>> connectors, study the specs, and study the operating instructions.
>>
>> 73, Jim K9YC
>>
>>
>>
>>> On Sat,8/22/2015 1:28 PM, Floyd Sense wrote:
>>> Hi Don. I'm sure you're aware that the RS232 spec includes the
>>> description of voltage levels, and if you're going to refer to an
>>> interface as RS232 (as Elecraft does in many places) then you're
>>> implying that the normal RS232 signal levels will be used. A user
>>> shouldn't be required to read a one hundred page manual before
>>> plugging in a connector when every other such connector works in the
>>> conventional way. Having been a designer using RS232 interfaces 45
>>> years ago, I would have been executed had I designed something like

Re: K2 - KPA100 RS232 interface repair

Some of the pins on the AUX I/O connector meet parts of the RS232 spec, but other of the pins are used for an elecraft proprietary expansion interface. So, from an electrical perspective you can say it is actually a mix of both RS232 (partial) and AUX I/O. From a physical connector perspective, it is definitely not RS232, which is why you need to make an isolation/breakout cable.

This is explained in the KIO2 manual. The main K2 manual doesn’t really seem to emphasize the point that severe damage can result if you connect this port directly to the serial port on a PC without making up an appropriate isolation/breakout cable. Due to the potentially serious consequences, I would have thought a warning in the main manual would be appropriate.

RJ45 is commonly used for RS232C. Millions of Cisco routers and switches
built over the past 20+ years use this arrangement, as do many other
devices. I have a half dozen of these cables - they once were shipped with
the router. Although I don't know for sure, I'll bet the pinout is the same
as Cisco.

I can make up 10 RJ45 connectors in the time it takes to make a soldered
DB9.

Historically, RS232 was used in electromagnetic applications where there was
a need to drive a relay with line levels. Since modern equipment doesn't
need this - since TTL became commonplace in the 1970's - and since many
lower power devices no longer have 12V power supplies, it has been practice
to observe a ONE state at a voltage of 3V+.

> On Aug 22, 2015, at 8:31 PM, Bob McGraw - K4TAX <[hidden email]>
wrote:
>
> The K3S has a RJ-45 connector for the RS-232 communications. Now that's
different! Of course they supply a cable with a RJ-45 on one end and a
DB-9F on the other. And then to keep everybody happy, there is what appears
to be a 15 pin VGA connector that is the ACC connector to provide band data
and such. The manual clearly states "This is not a VGA video connector".
>
> Yes it is very important to read and understand the manual before plugging
or inserting any connector into any hole on any radio today. It seems most
hams think if it plugs in, then it should work.

>
> 73
> Bob, K4TAX
> K3S s/n 10,163
>
>> On 8/22/2015 7:17 PM, Richard W. Solomon wrote:
>> It seems to me that using a DB-9 connector for non-RS232 uses is
>> taking the Easy way out.
>> There are numerous other connectors that could be used to alleviate
>> any Misunderstanding.
>>
>> Not everyone goes through manuals with a fine tooth comb to locate
>> the "gotchas".
>>
>> 73, Dick, W1KSZ
>>
>> -----Original Message-----
>> From: Elecraft [mailto:[hidden email]] On Behalf Of
>> Jim Brown
>> Sent: Saturday, August 22, 2015 4:25 PM
>> To: [hidden email]>> Subject: Re: [Elecraft] K2 - KPA100 RS232 interface repair
>>
>> Hi Floyd,
>>
>> I've owned and operated a pair of K2s, both of which I bought used.
>> Elecraft makes it very clear that the DB9 connector on the K2 is NOT
>> an
>> RS232 interface, that it is not RS232 compliant, and that a standard
>> RS232 cable should NOT be used. Rather, the DB9 connector provides
>> both serial control AND several control functions.
>>
>> The DB9 connector is a generic part, and can be used for many things
>> besides RS232. It is also well known that while the RS232 Standard
>> defines voltage levels, MANY modern products produce far less than those

levels.

>>
>> I've owned a lot of gear in my lifetime, and the first thing I do is
>> open the manual, study it, study the wiring of the various
>> connectors, study the specs, and study the operating instructions.
>>
>> 73, Jim K9YC
>>
>>
>>
>>> On Sat,8/22/2015 1:28 PM, Floyd Sense wrote:
>>> Hi Don. I'm sure you're aware that the RS232 spec includes the
>>> description of voltage levels, and if you're going to refer to an
>>> interface as RS232 (as Elecraft does in many places) then you're
>>> implying that the normal RS232 signal levels will be used. A user
>>> shouldn't be required to read a one hundred page manual before
>>> plugging in a connector when every other such connector works in the
>>> conventional way. Having been a designer using RS232 interfaces 45
>>> years ago, I would have been executed had I designed something like

Re: K2 - KPA100 RS232 interface repair

On 8/23/2015 1:21 AM, Richard W. Solomon wrote:
> Not to flog this horse any further, but I direct you to page 85 of the K2
> Manual where the DB-9 connector is labeled ..."RS-232 and AUX I/O"... .
>
> Is it RS-232 or not ??? Is it mis-labeled ????

RS-232 defines voltage levels (a bi-polar system greater than +3V or
less than -3V). It *does not define a connector*. The K2 Manual is
*entirely consistent* in saying RS-232 and Aux I/O ... the CAT pins
(2,3 & 5) are RS-232 levels, the others associated with Aux I/O (ALC,
Aux Bus, RF, +12, and 8R) are not.

Perhaps the DB connector associated with the KIO2 could be more artfully
described as "Auxiliary I/O" or Auxiliary I/O including RS-232 control
but the "RS-232 and AUX I/O" label is technically accurate.

Re: K2 - KPA100 RS232 interface repair

> The K3S has a RJ-45 connector for the RS-232 communications. Now
> that's different! Of course they supply a cable with a RJ-45 on one
> end and a DB-9F on the other. And then to keep everybody happy, there
> is what appears to be a 15 pin VGA connector that is the ACC connector
> to provide band data and such. The manual clearly states "This is not
> a VGA video connector".
>
> Yes it is very important to read and understand the manual before
> plugging or inserting any connector into any hole on any radio today.
> It seems most hams think if it plugs in, then it should work.
>
> 73
> Bob, K4TAX
> K3S s/n 10,163